A manufacturing method of an optical display device mounted to a conventional liquid crystal display device is conceptually shown in FIG. 6. First, in an optical filmmaker, a step produces a long (web-like) optical film as a material roll (#1). The concrete manufacturing step is a known manufacturing step, and a description thereof will not be given. As the long (web-like) optical film as a material roll, for example, there are a polarizing plate material, a retardation plate material, a laminated film material of the polarizing plate and the retardation plate, and the like which are used in a liquid crystal display device. Next, the material roll is slit to a predetermined size (a size in accordance with a size of the liquid crystal cell) (#2). Next, the slit long material is cut to a fixed size in conformity to a size of the liquid crystal cell (#3). Next, a step inspects an outer appearance of a piece of optical film cut to the fixed size (#4). As the inspecting method, for example, there can be listed up a defect inspection in accordance with a visual observation, and an inspection using a known defect inspection apparatus. The defect means, for example, a dirty in a front surface or an internal portion, a scratch, a special twisted defect like a hitting mark generated by biting a contaminant (which may be called as a knick), an air bubble, a contaminant or the like. Next, a step inspects a finished product (#5). The final product inspection is an inspection in accordance with a quality standard having a severer non-defective determination than the outer appearance inspection. Next, a step works end face treatment in four sides of the piece of optical film (#6). This step is carried out for preventing an adhesive or the like from running over from the end faces during transport. Next, a step cleanly packages the piece of optical film under a clean room environment (#7). Next, a step packages for transport (a transport package) (#8). The piece of optical film is produced as mentioned above, and is transported to a panel processing manufacturer.
In the panel processing manufacturer, a step opens the package of the piece of optical film transported (#11). Next, a step inspects an outer appearance for inspecting the scratch, the dirt and the like generated at a time of transporting or opening the package (#12). The piece of optical film which is determined as a non-defective by the inspection is fed to the next step. There is a case that the outer appearance inspection is omitted. A liquid crystal cell to which the piece of optical film is bonded is previously produced, and the liquid crystal cell is cleaned before the bonding step (#13).
A step bonds the piece of optical film to the liquid crystal cell (#14). A release film is peeled off from the piece of optical film while leaving a pressure-sensitive adhesive layer, and it is bonded to one face of the liquid crystal cell by using the pressure-sensitive adhesive layer as a bonding surface. Further, it can be bonded to the other surface of the liquid crystal cell in the same manner. In the case of bonding to both the surfaces, the structure may be made such that the optical films having the same construction are bonded to the surfaces of the liquid crystal cell, or the structure may be made such that the optical films having different constructions are bonded thereto. Next, a step carries out an inspection of the optical display device in the state in which the optical film is bonded and a defect inspection (#15). The optical display device which is determined as a non-defective in this inspection is fed to a mounting process to be mounted (#16). On the other hand, a reworking process is applied to the optical display device which is determined as a defective (#17). In the reworking process, the optical film is peeled off from the liquid crystal cell. The optical film is newly bonded to the reworked liquid crystal cell (#14).
In the manufacturing step mentioned above, since the optical film maker and the panel processing manufacturer exist in the separate places, the end face treatment, the packaging of the piece of optical film, the package opening and the like are particularly necessary steps. However, there are a problem of a manufacturing cost increase caused by multiple steps, a problem of the scratch, the dust, the dirt and the like generated by the multiple steps and the transport, a necessity of the inspection step caused thereby, and a problem that it is necessary to store and manage many kinds of optical films as a stock.
As a method of solving the problems, there has been proposed Japanese Unexamined Patent Publication No. 2007-140046 (Patent Document 1). In accordance with this method, the structure is provided with supply means pulling out and supplying a long optical film from a material roll around which the optical film corresponding to a member of an optical display device is wound, detection means detecting a defect of the optical film pulled out by the supply means, cutting work means cutting the optical film based on a result of detection of the detection means and working to an individual optical film, transfer means transferring the optical film cut by the cutting work means for a bonding work, and bonding work means bonding the optical film transferred by the transfer means to a liquid crystal cell which is a member of an optical display device, and these means are arranged on a continuous manufacturing line. In the structure mentioned above, it is possible to directly cut the long optical film into a desired size, and to bond the cut optical film to the liquid crystal cell. Accordingly, it is possible to directly package the long optical film wound around the material roll so as to deliver, in place of the conventional step which stamps the long optical film, tightly packages the stamped optical film, and delivers to the panel processing manufacturer.
In Japanese Unexamined Patent Publication No. 2005-37416 (Patent Document 2), there is disclosed an example of a technique for cutting a long optical film (a long film), and bonding the film to a liquid crystal cell (a substrate) as mentioned above. In this technique, there is employed a polarizing plate in which a polarization axis (a transmission axis) is oriented in parallel to a film longitudinal direction, or a polarizing plate in which a polarization axis is oriented vertically to the film longitudinal direction.
In Japanese Unexamined Patent Publication No. 2005-37417 (Patent Document 3), there is disclosed a structure in which a direction of a polarization axis (a direction of a transmission axis) of a film piece bonded to one surface of a liquid crystal cell is oriented vertically to a direction of a polarization axis of a film piece bonded to the other surface, at a time of bonding the films to both surfaces of a liquid crystal cell (a substrate) after cutting a long optical film (a long film).